<?php

namespace App\Services\ModelCache;

class Builder extends \Illuminate\Database\Query\Builder
{
    /**
     * The key that should be used when caching the query.
     *
     * @var string
     */
    protected $cacheKey;
    /**
     * The number of minutes to cache the query.
     *
     * @var int
     */
    protected $cacheMinutes;
    /**
     * The tags for the query cache.
     *
     * @var array
     */
    protected $cacheTags;
    /**
     * The cache driver to be used.
     *
     * @var string
     */
    protected $cacheDriver;
    /**
     * A cache prefix.
     *
     * @var string
     */
    protected $cachePrefix = 'modelcache';

    /**
     * Execute the query as a "select" statement.
     *
     * @param  array $columns
     * @return array|static[]
     */
    public function get($columns = ['*'])
    {
        if (!is_null($this->cacheMinutes)) {
            return $this->getCached($columns);
        }
        return parent::get($columns);
    }

    /**
     * Execute the query as a cached "select" statement.
     *
     * @param  array $columns
     * @return array
     */
    public function getCached($columns = ['*'])
    {
        if (is_null($this->columns)) {
            $this->columns = $columns;
        }
        // If the query is requested to be cached, we will cache it using a unique key
        // for this database connection and query statement, including the bindings
        // that are used on this query, providing great convenience when caching.
        $key = $this->cachePrefix . ':' . ($this->cacheKey ?: hash('sha256', $this->connection->getName() . $this->toSql() . serialize($this->getBindings())));
        $cache = $this->getCache();
        $callback = $this->getCacheCallback($columns);
        // If the "minutes" value is less than zero, we will use that as the indicator
        // that the value should be remembered indefinitely and if we have minutes
        // we will use the typical remember function here.
        if ($this->cacheMinutes < 0) {
            return $cache->rememberForever($key, $callback);
        }
        return $cache->remember($key, $this->cacheMinutes, $callback);
    }

    /**
     * Indicate that the query results should be cached.
     *
     * @param  \DateTime|int $minutes
     * @param  string $key
     * @return $this
     */
    public function remember($minutes, $key = null)
    {
        list($this->cacheMinutes, $this->cacheKey) = [$minutes, $key];
        return $this;
    }

    /**
     * Indicate that the query results should be cached forever.
     *
     * @param  string $key
     * @return \Illuminate\Database\Query\Builder|static
     */
    public function rememberForever($key = null)
    {
        return $this->remember(-1, $key);
    }

    /**
     * Flush the cache for the current model or a given tag name
     *
     * @param  mixed $cacheTags
     * @return boolean
     */
    public function cacheFlush($cacheTags = null)
    {
        $store = app('cache')->getStore();
        if (!method_exists($store, 'tags')) {
            return false;
        }
        $cacheTags = $cacheTags ?: $this->cacheTags;
        $store->tags($cacheTags)->flush();
        return true;
    }

    /**
     * Set the cache prefix.
     *
     * @param string $prefix
     *
     * @return $this
     */
    public function cachePrefix($prefix)
    {
        $this->cachePrefix = $prefix;
        return $this;
    }

    /**
     * Indicate that the results, if cached, should use the given cache tags.
     *
     * @param  array|mixed $cacheTags
     * @return $this
     */
    public function cacheTags($cacheTags)
    {
        $this->cacheTags = $cacheTags;
        return $this;
    }

    /**
     * Indicate that the results, if cached, should use the given cache driver.
     *
     * @param  string $cacheDriver
     * @return $this
     */
    public function cacheDriver($cacheDriver)
    {
        $this->cacheDriver = $cacheDriver;
        return $this;
    }

    /**
     * Get the cache object with tags assigned, if applicable.
     *
     * @return \Illuminate\Cache\CacheManager
     */
    protected function getCache()
    {
        $cache = app('cache')->driver($this->cacheDriver);
        return $this->cacheTags ? $cache->tags($this->cacheTags) : $cache;
    }

    /**
     * Get the Closure callback used when caching queries.
     *
     * @param  array $columns
     * @return \Closure
     */
    protected function getCacheCallback($columns)
    {
        return function () use ($columns) {
            $this->cacheMinutes = null;
            return $this->get($columns);
        };
    }
}